Electric switching device



United States Patent Ofiice 3,328,552 Patented June 27, 1967 3,328,552 ELECTRIC SWITCHING DEVICE Joseph J. Gribble, Milwaukee, and Merlin Y. Turnbnll, Broolrfield, Wis., assignors to Square I) Company, Park Ridge, 111., a corporation of Michigan Filed Apr. 4, 1966, Ser. No. 539,699 Claims. (Cl. 200-168) This invention relates to electric switching devices and is more particularly concerned with a self-contained electric switch having a cover that may be removed to permit inspection and replacement of the switch contacts and carries a portion of a means for cooling arcs formed between the switch contacts and a means for guiding the movable contacts of the switch during their operation.

It is an object of the present invention to provide an electric switch with a novel means for cooling arcs formed between the contacts of the switch which will not interfere with the inspection, installation or reversal of the switch contacts.

Another object is to provide an electric switch with one or more pairs of stationary contact assemblies, with each assembly being identical and detachably and reversibly mountable in the switch to provide the switch with a normally open or a normally closed contact operation and to surround the contacts with an arc cooling means, a portion of which is carried by a cover that may be readily removed to provide free access to the contacts, and to provide the cover with means for guiding the movable contacts of the switch.

Another object is to provide an electric switch with novel stationary and movable contact structures that occupy a minimum space and a means for cooling arcs formed during the operation of the contacts, said stationary contacts having a wire connecting portion reversibly mountable on a base of the switch, a mounting portion detachably and reversibly mounted on the base in electrical engagement with the wire connecting portion and a contact surface portion integral with and offset from the mounting portion such that the offset of the contact portion is reversed when the mounting portion is reversed, said movable contact portion being carried by a carrier that is movable in a linear path along a centerline between two spaced and oppositely facing stationary contacts and including a bridging member having at each end a contact surface extending beyond the carrier and offset by an amount equal to the offset of the stationary contacts and a spring biasing the bridging member in one direction on the carrier with the spring and bridging member beingreversible end for end to reverse the direction of the bias and the offset of the contact surfaces on the bridging member whereby the switch is convertible to provide a normally open and a normally closed operation of the contacts with the arc cooling means cooling the arcs in either mode of operation of the switch and to provide a readily removable cover for the switch which carries a portion of the arc moving means and provides a guide for the carrier during its movements as well as provides an arrangement which will permit easy access for the inspection and replacement of the contacts.

Further objects and features of the invention will be readily apparent to those skilled in the art from the specification and appended drawing illustrating a preferred embodiment, in which:

FIG. 1 is an elevational view of an end of a switch incorporating the features of the present invention.

FIG. 2 is an elevational view of the switch in FIG. 1 taken in the direction of arrow 2.

FIG. 3 is an elevational view of the switch in FIG. 1 taken in the direction of arrow 3.

FIG. 4 is an elevational view of the switch in FIG. 2

with the cover removed and the switch in a deactuated condition.

FIG. 5 is an elevational view of the inside surface of the cover for the switch in FIG. 4.

FIG. 6 is a view of the switch as in FIG. 2 with a portion of the cover broken away to illustrate details of the switch contact structure when the switch is in an actuated condition.

FIG. 7 is an exploded view showing in perspective the parts of the stationary contact assembly and arc cooling means of the switch in FIG. 6.

The switch assembly 20, as shown in the drawings, includes a housing or base 22, mounted on a U-shaped channel-like member 24, a cover 26, a carrier 28 which acts as a movable contact guide and support assembly, a return spring 30, and one or more pairs of stationary contact assemblies.

The base 22 and the cover 26 each have a pair of rectangular openings 34 and 36 aligned along the vertical centerline 38 of the switch assembly 20. The, base 22, which is preferably formed of a suitable molded insulating material, is formed to have a solid rear wall 40 wherein the openings 34 and 36 are located, and one or more pairs of cavities 4142 and 43-44 which are located on opposite sides of a centerline 38, as shown in FIG. 4. Each of the cavities 41-44, which is connected by a passage 56 to an opening 57 in an adjacent side wall of the base 22, has a stationary contact assembly 46 mounted therein.

The stationary contact assembly 46 in each cavity 41-44 is formed of identical parts and, as shown in FIG. 7, includes a terminal member 48 having a box lug-type wire connecting portion 50 at one end for clamping a bared end of an electrical conductor, not shown. The terminal member 48 has a portion 52 extending upwardly at an angle from the box-lug portion 50 to a mounting portion 54 that extends in a plane perpendicular to the portion 52 along the centerline of the box-lug portion 50. As most clearly shown in FIG. 6, each passage 56 has a raised mounting boss 58 therein which has a side wall 59 facing the respective cavities 41-44, a sidewall '60 partly obstructing the opening 57 and a front wall 61 extending between the walls 59 and 60. The front wall 61 has a threaded insert 62 embedded in the material of the base 22. Additionally, each boss 58 has a top wall 63 and a bottom wall 64 spaced from the walls of the base 22 defin ing the passage 56. Eachof the portions 54 is provided wit-h an opening 65 which is received by a lip portion of the insert 62 that projects above the front wall 61 for securing the portion 54 to the top wall '61 and the lip portion of the insert 62 is staked over the portion 54. The inclined portion 52 additionally has a threaded opening 66 which receives a screw '68 to secure a metal platelike member 70. The members 70 each have an opening 71 located to receive the screw 68 and permit the position of the members 70 to be reversed on the portion 52. Thus as the mounting portion 54 extends along a plane through the centerline of the lug portion 50, the wire connecting members 48 may be mounted on bosses 58 on either the right or left sides of the centerline 38. When the wire connecting members 48 are positioned on opposite sides of the centerline 38, the members 70 may be positioned to close the passages 56 to prevent inadvertent entry of a tool into the cavities 41-44 and to aid in cooling gases formed during operation of the switch contacts.

The, stationary contact assemblies 46, shown in FIG. 7, each additionally include a stationary contact member 72 having a mounting portion 74 detachably and reversibly mounted on the mounting portions 54 by a screw 75 that is secured in the inserts 62 when the terminal members 48 are secured on the front walls 61 as described. The mounting portion 74 extends perpendicular to a base 76 that has an end 78 offset from the mounting portion 74. A contact surface 80 is located on the offset end 78. The mounting portion 74 extends in a plane which is perpendicular and bisects the cont-act surface 80. Each of the bosses 58 are formed in the passages 56 to provide a space between walls 63and 64 and the walls of the base 22 defining the passages 56. These spaces are designated by the numeral 82 and are arranged to receive the base portion 76 when the stationary contact members 72 are positioned to have the base portion 76 extending toward the rear wall 40, as in FIG. 6. When the stationary contact members 72 are positioned in the cavities 41-44, as shown in FIG. 4, the base portions 76 will extend toward the cover 26. Thus the stationary contact members 72 may be mounted in either of two positions in each cavity. This arrangement will permit the stationary contacts to be mounted to present a contact surface on both sides of the centerline 38 in each cavity 4144 which will face either the top or bottom ends of the switch 20. Thus when the position of the mounting portions 74 on the bosses 58 in the cavities 4144 is reversed, the direction in which the contact surface 80 faces and the angle of offset of the contact surface 80 with respect to a perpendicular to the centerline 38 will be reversed.

The movable contact guide and support assembly 28 includes a contact carrier 86 preferably formed of model insulating material to have a rectangular cross section with a rear wall, not shown, parallel to a front wall 88 and side walls 90 and 92. The rear wall and the front wall 88 each have a pair of space-d rectangular projections 94 received in the openings 34 and 36 in the cover 26 and the base 22 when the cover 26 is assembled to the base 22. The openings 34 and 36 in the base 22 and the cover 26 and the projections 94 are arranged to guide the movable contact carrier 86 during its movements along the centerline 38. Prefer-ably three of the projections 94 are formed to present an outer surface which is flush with the exterior surfaces of the rear wall 40 and the cover 26. One of the projections, however, e.g., a projection designated as 94a, is formed to extend externally of the rear wall 40 to provide a means whereby the carrier 86 may be moved internally in the switch 20 when a suitable external force is applied to the projection 94a. Axially spaced along the carrier 86 and extending between the side walls 90 and 92 are a pair of identical rectangular openings 96 that are horizontally aligned with the cavities 41-42 and 43-44;

Each of the openings 96 has a pair of spaced oppositely facing end walls 102 and 104. The outer edges of the end walls 102 and 104 are provided with a bevel edge 106. The area of the walls 102 and 104 between the bevel edges 106 is indented to provide a spring seat 108.

Movably mounted in each of the opening 96 is a movable contact assembly 109 and a spring 116. The contact assembly 109 includes a bridging member 110 formed of conducting material to have a central portion 112 which is guided by the side walls of the openings 96. The central portion 112 is provided with a raised centrally located circular boss 114 which receives one end of the compression spring 116. The marginal edges of the central portion 112 are curved to form inclined portions 118 that are shape-d to conform to the bevelled edges 106 and position the central portion 110 on the walls 102 and 104. Extending outwardly from the inclined portions 118 beyond the side walls 90 and 92 of the carrier 86 are ends 120 which are offset at an angle with respect to a perpendicular to the centerline 38. The offset ends 120 each have a contact surface 122 thereon which is offset with respect to the centerline by an amount equal to the offset of the contact surfaces 80.

The bridging members 110 may be positioned in the opening 96 againsteither end wall 102 or 104 by the springs 116. The springs 116 each are of the compression type and have one end positioned on the spring seat 108 on one of the end walls 102 or 104 and the other end positioned by the circular boss 114 to constantly urge 4 the bridging member .in a direction away from the seat 108 whereon the spring 116 is positioned.

Each of the movable contact assemblies 109 may be positioned to face in opposite directions on the opening 96. Thus when the bridging member 110 and spring 116- are positioned as shown in FIG. 4, the contact surfaces 122 will be biased by the springs 116 to engage the contact surfaces 80 adjacent the top end of the cavities 41 and 42 and the cavities 43 and 44. Similarly, when the position of the springs 116 and the contact assemblies 109 are reversed end for end and positioned as shown in FIG. 6, and the position of the stationary contact members 72 are similarly reversed, the contact surfaces 122 will be biased by the springs 116 to engage the contact surfaces 80 located at the bottom ends of the cavities 41-42 and the cavities 4344. The spring 30 biases the carrier 28 upwardly in the base 22. Thus during the absence of an external force on the projection 94a, the spring 30 will bias the movable contact assemblies 109 upwardly in the base 22 and if the stationary contacts 72 are positioned as shown in FIG. 4, the switch 20 will have normally closed contacts which will open upon the application of a switchable external force on the projection 9411. Similarly, when the stationary contacts 72 and the movable contact assemblies 109 are positioned as in FIG. 6, the switch ,will have normally open contacts which will be closed upon application of a suitable externally applied force on the pro jection 94a which will cause the carrier 86 to move downwardly in the base 22 against the bias of spring 30.

The cover 26 has surface configured to provide cavities 41a, 42a, 43a, and 44a, passages 56a and bosses 58a having a lesser depth and the same shape as the cavities 41-44, the passages 56 and the bosses 58 which are provided by the base 22. The cover 26 and the base 22 respectively have portions 132 and 132a extending downwardly through an opening 134 in the channel-like member 24 which provides a recess 135 that is preferably cylindrical and acts as a seat for the spring 30. Additionally, the base 22 is pr-ovided with a pair of cavities 136 which receive a pair of projections 138 on the cover 26 to position the cover 26 on the base 22. The cover 26 is secured to the base 22 by a pair of screws 140 extending through a pair of openings 142 in they cover and threaded into a pair. of inserts 144 which are molded in the base 22.

Secured in each cavity 41-44 in the base 22 and in each cavity 41a-44a in the cover 26 are identical L-shaped arc cooling members 150, the shape of which is most clearly seen in FIG. 7. Each member has abase portion 151 secured, as by riveting, to a raised boss 152 which is shaped as shown in FIG. 6 and extends from'the rear walls 40 and 40a in each cavity 41-44 and 4161-444- The bosses 152 preferably are sized to space a substantial portion of the rear surfaces 153 of the base portions 151 from the walls 40 and 40a of the base 22 and the cover 26 to aid in cooling of the member 150.

The base portions 151 are generally trapezoidal in shape having parallel edges 154 and 155 and angular edges 156 and 157 and are positioned in the cavities 41-44 and 41a-44a so the longer, parallel edge 154 is adjacent the side walls 90 and 92 of the contact carrier 86 and the shorter parallel edge 155 extends to present an .arm portion 158 which extends perpendicular to the base portion 151 adjacent the side walls 59 of the bosses 58. The portions 158 have a free end 159 which is flush with the.

front wall 61 when member 150 is secured to the base 22. However, as the bosses 58a on the cover 26 are shallower than the bosses 58 on the base 22, the free ends 159 of the members 150 mounted on the cover 26 extend substantially beyond the front walls 61a on the cover 26 which correspond to the front walls 61 on the base 22. The portions 158 are sized so the ends 159 on the member 150 mounted on the cover 26 and the base 22 will be juxtaposed when the cover 26 is secured on the base 22 to thereby provide an arc cooling meansv which is continuous and substantially surrounds the stationary contact surfaces 80 and the movable contact surfaces 122. Preferably, the edges 156 and 157 extend at the same angle relative to a perpendicular to centerline 38 as the offset ends 78 and 120 and are located so the edges 156 and 157 are in planes passing through the con-tact surfaces 80. Thus the members 150 will present a metal surface adjacent both contact surfaces 80 and 122 as the surfaces separate.

The base 22 is secured to the member 24 by screws 160 which pass through openings in the base into threaded openings 162 in the member 24. The switch 20 may be secured adjacent the side Wall of a switch operating mechanism in a manner disclosed in application Ser. No. 473,- 299, filed July 20, 1965, which has been assigned by the inventors to the assignee of the present invention.

When the switch 20 is attached to the switch operating mechanism as disclosed in the application supra, the wall 40 will be positioned adjacent the operating mechanism so the switch 20 may be actuated through the projection 94a. When the switch 20 is thus mounted, inspection and replacement of the stationary and movable contacts of the switch 20 may be readily accomplished by removing the cover 26. The removal of the cover 26 is accomplished by loosening screws 140 and lifting the cover from its engaging position with the base 22. The removal of the cover will also cause the removal of the contact cooling members 150 which are carried by the cover so that an unimpeded access will be provided to both the stationary contacts and movable contacts which are on the base 22. This unimpeded access is achieved by supporting cooperating portions of the arc cooling means on the base 22 and the cover 26, as described.

While certain preferred embodiments .of the invention have been specifically disclosed, it is understood that the invention is not limited thereto, as many variations will be readily apparent to those skilled in the art and the invention is to be given its broadest possible interpretation within the terms of the following claims.

What is claimed is:

1. An electric switch comprising: a base formed of molded insulating material to have a solid rear wall and an open front wall exposing at least one pair of cavities which are disposed on opposite sides of a centerline through the said base, a pair of stationary contact assemblies with each one of said pair of stationary contact assemblies mounted on the base in one of the said pair of cavities, each of said stationary contact assemblies being identical and comprising a mounting portion detachably and reversibly mounted on the rear wall and each of said stationary contact assemblies further comprising a contact surface offset from the mounting portion such that the direction of offset of said contact surface is reversed when the mounting portion is reversed, a molded contact carrier reciprocally movable in a linear path along the centerline between the contact surfaces, a movable contact assembly including a bridging member carried by and extending beyond opposite sides of said carrier and having at each end a contact surface offset therefrom by an amount equal to the oifset of said stationary contact surfaces, and a spring biasing said bridging member in one direction on the said carrier, said spring and bridging member being reversible end for end to reverse the direction of said bias and the offset of the contact surfaces on the bridging member whereby the switch is convertible to provide a normally open and a normally closed operation of the contacts, a removable cover for the front wall closing the cavities when the cover is secured to the base and exposing the stationary contacts and the movable contact assembly when the cover is detached from the base, said cover and base each having a pair of spaced openings in alignment along the centerline, and projections on the carrier movable in said openings guiding the carrier in its linear path of movement with one of said projections including an extension which projects beyond the exterior surface of the rear wall providing a means for actuating the switch.

2. An electric switch comprising: a base formed of molded insulating material to have a solid rear wall and an open front wall exposing at least one pair of cavities which are disposed on opposite sides of a centerline through the said base, a pair of stationary contact assemblies with each one of the said pair of stationary contact assemblies mounted on the base in one of the said pair of cavities, each of said stationary contact assemblies being identical and comprising a mounting portion detachably and reversibly mounted on the rear Wall and each of said stationary contact assemblies further comprising a contact surface offset from the mounting portion such that the direction of olfset of said contact surface is reversed when the mounting portion is reversed, a molded contact carrier reciprocally movable in a linear path along the centerline between the contact surfaces, a movable contact assembly including a bridging member carried by and extending beyond opposite sides of said carrier and having at each end a contact surface offset therefrom by an amount equal to the offset of said stationary contact surfaces, and a spring biasing said bridging member in one direction on the said carrier, said spring and bridging member being reversible end for end to reverse the direction of said bias and the offset of the contact surfaces on the bridging member whereby the switch is convertible to provide a norm-ally open and a normally closed operation of the contacts, a removable cover for the front wall closing the cavities when the cover is secured to the base and exposing the stationary contacts and the movable contact assembly when the cover is detached from the base, and means for cooling electrical arcs formed between the contact surfaces on the stationary contact assemblies and the movable contacts during operation of the contacts, said means including a pair of cooperating L-sh-aped members individual to each cavity, each of the members having a base portion and an arm portion with corresponding portions of the base portions of the L-shaped members respectively secured to the rear wall and to a surface of the cover facing the cavity so the free ends on the arm portions of each individual pair of members are juxtaposed to each other when the cover is secured to the base.

3. The combination as recited in claim 1 wherein a cylindrical recess formed by portions of the base and the cover positions a spring which has an end engaging the carrier.

4. The combination as recited in claim 1 which includes a U-shaped channel-like member having portions engaging exterior surface portions of the rear wall and the cover for mounting the switch on a support.

5. The combination as recited in claim 1 wherein the base is provided with an additional pair of cavities which are axially spaced along opposite sides of the centerline from the said one pair of cavities and the additional pair of cavities each have a stationary contact assembly therein which is identical with the stationary contact assembly in each cavity of the said one pair of cavities and the carrier provides a support for an additional movable contact assembly which is identical to and cooperates with the stationary contacts in the said additional cavities in a manner identical to the operation of the movable contact assembly with the stationary contacts assembly in the said one pair of cavities whereby the contacts of the switch may be arranged to selectively provide the switch with two normally open pairs of contacts, two normally closed pairs of cont-acts and one normally open and one normally closed pairs of contacts.

6. The combination as recited in claim 2 wherein the base is provided with an additional pair of cavities which are axially spaced along opposite sides of the centerline from the said one pair of cavities and the additional pair of cavities each have a stationary contact assembly therein which is identical with the stationary contact assembly in each cavity of the said one pair of cavities, the carrier provides a support for an additional movable contact assembly which is identical to and cooperates with the stationary contacts in the said additional cavities in a manner identical to the operation of the movable contact assembly with the stationary contacts assembly in the said one pair of cavities and each of the additional cavities and the cover is provided with a means for cooling the electrical arcs which is identical to the arc cooling means of the said one pair of cavities whereby the contacts of the switch may be arranged to selectively cause the switch to operate with two normally open pairs of contacts, two normally closed pairs of contacts and one normally open pair and one normally closed pair of contacts and to cool the arcs formed between the contacts regardless of the mode of operation of the switch contacts.

7. The combination as recited in claim 1 wherein each cavity extends to an opening in a side wall of the base and each stationary contact assembly includes a box lugtype wire connecting terminal member reversibly mounted on the rear wall in electrical engagement with the mounting portion and a member detachably and reversibly mounted on the terminal member for closing the opening into the cavity.

8. The combination as recited in claim 2 wherein the base portion of each'L-shaped member has a truncated triangle shape having the arm portion extending from a truncated edge of the member.

9. The combination as recited in claim 2 wherein each cavity extends to an opening in a side wall of the base and each stationary contact assembly includes a box lugtype wire connecting terminal member reversibly mounted on the rear wall in electrical engagement with the mounting portion and a member detachably and reversibly mounted on'the terminal member for closing the opening into the cavity and wherein the base portion of each L-shaped member has a truncated triangle shape having the arm portion extending from a truncated edge of the References Cited UNITED STATES PATENTS 2,822,450 2/1958 Goudy et al. 200166 3,045,092 7/1962 Bundy 200-168 3,099,728 7/1963 Scheib 200-l66 3,188,405 6/1965 Scheib 200166 ROBERT K. SCHAEFER, Primary Examiner.

H. O. JONES, Assistant Examiner. 

1. AN ELECTRIC SWITCH COMPRISING: A BASE FORMED OF MOLDED INSULATING MATERIAL TO HAVE A SOLID REAR WALL AND AN OPEN FRONT WALL EXPOSING AT LEAST ONE PAIR OF CAVITIES WHICH ARE DISPOSED ON OPPOSITE SIDES OF A CENTERLINE THROUGH THE SAID BASE, A PAIR OF STATIONARY CONTACT BLIES WITH EACH ONE OF SAID PAIR OF STATIONARY CONTACT ASSEMASSEMBLIES MOUNTED ON THE BASE IN ONE OF THE SAID PAIR OF CAVITIES, EACH OF SAID STATIONARY CONTACT ASSEMBLIES BEING IDENTICAL AND COMPRISING A MOUNTING PORTION DETACHABLY AND REVERSIBLY MOUNTED ON THE REAR WALL AND EACH OF SAID STATIONARY CONTACT ASSEMBLIES FURTHER COMPRISING A CONTACT SURFACE OFFSET FROM THE MOUNTING PORTION SUCH THAT THE DIRECTION OF OFFSET OF SAID CONTACT SURFACE IS REVERSED WHEN THE MOUNTING PORTION IS REVERSED, A MOLDED CONTACT CARRIER RECIPROCALLY MOVABLE IN A LINEAR PATH ALONG THE CENTERLINE BETWEEN THE CONTACT SURFACES, A MOVABLE CONTACT ASSEMBLY INCLUDING A BRIDGING MEMBER CARRIED BY AND EXTENDING BEYOND OPPOSITE SIDES OF SAID CARRIER AND HAVING AT EACH END A CONTACT SURFACE OFFSET THEREFROM BY AN AMOUNT EQUAL TO THE OFFSET OF SAID STATIONARY CONTACT SURFACES, AND A SPRING BIASING SAID BRIDGING MEMBER IN ONE DIRECTION ON THE SAID CARRIER, SAID SPRING AND BRIDGING MEMBER BEING REVERSIBLE END FOR END TO REVERSE THE DIRECTION OF SAID BIAS AND THE OFFSET OF THE CONTACT SURFACES ON THE BRIDGING MEMBER WHEREBY THE SWITCH IS CONVERTIBLE TO PROVIDE A NORMALLY OPEN AND A NORMALLY CLOSED OPERATION OF THE CONTACTS, A REMOVABLE COVER FOR THE FRONT WALL CLOSING THE CAVITIES WHEN THE COVER IS SECURED TO THE BASE AND EXPOSING THE STATIONARY CONTACTS AND THE MOVABLE CONTACT ASSEMBLY WHEN THE COVER IS DETACHED FROM THE BASE, SAID COVER AND BASE EACH HAVING A PAIR OF SPACED OPENINGS IN ALIGNMENT ALONG THE CENTERLINE, AND PROJECTIONS OF THE CARRIER MOVABLE IN SAID OPENINGS GUIDING THE CARRIER IN ITS LINEAR PATH OF MOVEMENT WITH ONE OF SAID PROJECTIONS INCLUDING AN EXTENSION WHICH PROJECTS BEYOND THE EXTERIOR SURFACE OF THE REAR WALL PROVIDING A MEANS FOR ACTUATING THE SWITCH. 